A popular anti-drug program with ties to the Church of Scientology will be ousted after 13 years in the San Francisco schools unless it agrees to stop teaching what the district calls inaccurate and misleading information, Superintendent Arlene Ackerman said Wednesday.

The district's ultimatum means that Narconon Drug Prevention & Education has until June 24 to revise parts of its curriculum, said Ackerman, whose health education staff no longer wants the program to make sweeping generalizations about all drugs or claim that drugs are stored in fat for years.

"The fact that (Narconon) is addressing drugs is a positive," Ackerman said. "But some of the facts that they were teaching the kids support a philosophical or religious belief, as opposed to science, so we had to say 'no. ' "

Narconon must make the requested changes or be "removed from the list of Community Based Organizations" given to San Francisco schools, according to a letter faxed Wednesday by the district to Narconon's education director, Tony Bylsma.

Bylsma, who works out of Narconon's headquarters in Hollywood, said he had not decided whether to comply with the district's demand.

"We don't want to desert the kids," he said. "I'm going to decide how we're going to respond."

It is unclear whether being removed from the district's list of approved organizations would prevent individual schools from hosting Narconon anyway, said Board of Education PresidentDan Kelly.

"This may require an action of the board," Kelly said. "We're not going to have cults and religions preaching their line in our schools."

The district sent the letter the same day that The Chronicle published stories about Narconon. The stories raised questions about the science being taught and reported that religious concepts embraced by the Church of Scientology have found their way into classroom lectures to students.

Narconon was created by the late science fiction writer L. Ron Hubbard, who founded the Church of Scientology. Narconon officials say they have reached 30,000 San Francisco students since 1991, when they began providing free lectures in the city's schools. The program is also in Los Angeles and Orange County schools and in other states. Officials say they have reached 1.7 million students nationwide in the past decade.

Scientology correspondence reveals that Narconon instructors are taught to purge church language from their classroom instruction while including "all the Scientology and Dianetics Handbook basics." Narconon's anti-drug instruction also rests on key church concepts that the body stores all kinds of toxins indefinitely in fat, where they cause repeated flashbacks and drug cravings until "sweated out."

Yet the ideas have relevance in the Church of Scientology, which promotes a sauna program called Purification to "cleanse" the body of toxins believed to prevent church members from reaching a spiritually pure state, according to Hubbard's Scientology text "Clear Body, Clear Mind."

Ackerman said she took an interest in Narconon's curriculum after being contacted by The Chronicle months ago with questions about the program. She then asked her staff to see whether Narconon was "aligned with what we want our students to know and be able to do."

On Feb. 20, the district faxed a letter to Bylsma complaining that basic information about addiction was missing from its written curriculum and identifying one inaccurate statement, two misleading statements, and pointing to a Narconon newsletter containing information "not substantiated by any reputable authority." The newsletter was poised to go out to students and teachers.

The letter from Kim Coates, a district health administrator, asked Bylsma to clarify these statements in Narconon's curriculum:

-- "All drugs are basically poisons. The amount which you take is what determines the effect. A small amount acts as a stimulant (speeds you up). A larger amount acts as a sedative (puts you to sleep). An even larger amount acts as a poison and can kill you. This is true of any drug."

Coates said that statement was wrong.

-- "Most drugs or their byproducts get stored in fat within the body and can stay there for years. Even occasional use has long-term effects. This is a problem because later, when the person is working or exercising or has stress, the fat burns up and a tiny amount of the drug seeps back into the blood. This triggers cravings so the person may still want drugs even years after he's stopped taking them."

Coates called the statement misleading. Other medical experts, quoted in Wednesday's stories, said there is no evidence to support Narconon's claim that drugs stay in fat for years or that cravings are caused by drug residue in fat.

-- "Like any other drug it is poisonous to your body. ... Alcohol is made of dead rotted food."

Coates said both statements were misleading and asked that they be removed from the curriculum.

Three months later, on May 24, Bylsma sent the district a nine-page defense of Narconon's curriculum.

"There is sound science behind the basic truths we present to children," Bylsma wrote. He said that all of the statements in dispute were accurate and that to make the information more complex would bore the students.

"Let's be frank," he wrote. "Do you seriously think we will do better (with students) if we just parrot what others are saying and do not offer a fresh point of view?"

On Wednesday, Coates replied that unless Narconon made the requested changes to its curriculum, "the organization will be removed" from the district's list.